Economical methods to improve production from Mature Gas Fields

Transcription

1 Economical methods to improve production from Mature Gas Fields A preliminary report on gas production optimization: focusing on ejector (eductor), chemicals and vortex tools technologies to revive mature gas fields nizam@petrosol.co

2 Content Objective Liquids Loading in Gas Wells Ejector (Eductor/velocity spool) Surfactants Liquids Unloading with Vortex Tool Conclusion

3 Objective Optimize production with minimum CAPEX/OPEX Maximize utilization of the existing surface production facilities No wellhead or bottomhole modifications Focus on downhole/surface vortex technology, eductors (ejectors) and chemical surfactants/foamers

4 Well s energy depreciation

5 Liquids loading Gas rate below critical value, cannot effectively contribute to transport liquid to surface, resulting accumulation of downhole liquids!!

6 Predicting liquid loading Critical velocity concept Droplet reversal model Film reversal theory J curve method

7 Ejector or Gas Jet Compressor Lowering WHP and increasing production LP_well: 30 b, 200 knm3/d 50 b Suction pressure of compressors HP_Well: 150b Flow 500 knm3/d

8 Ejector (Eductor or Velocity Spool) Increased gas production Gas jet ejector performance

9 Surfactant/foamer Well Diagnostics Static & Dynamic bottomhole temperature Static & Dynamic bottomhole pressure Wellhead Pressure Tubing ID Formation Fluid Analysis Depth Gas Production rates, etc. Non Ionic Compounds of phenols or alcohols Good for unknown water chemistry Less emulsion prone Lab Tests (Bottle Test, Blener Test, Dynamic Test) Surfactant Selection Field Trial(s) Anionic Alkyl ether sulphates and alpha-olefin sulphonates Escellent water foamer Degrate at 125 C+ Application and Assessment Diagnostic Treatment(s) Routine Application Application Administration Cationic Quaternary amines Better in brine than fresh water good for foaming mixtures of oil and brine Amphoteric Adaptable based on ph values Stable at 200F+ and salt content (10 wt % +)

10 Surfactant/foamer application Capillary String

11 Capillary String Injection Cap string injection Relatively simple application Can be applied to wide range of completion (monobore, Short/Long String with nipple profile, selective produce through sliding sleeve, etc) Liquid soap/surfactant is easy to inject across perforation Continuous liquid soap injection maintain the gas velocity above the critical velociy for certain periods. However, to keep the well unloaded for a longer period of time requires continuous optimization. Cap-String Component : ¼ Capillary String Bulk Tank for Chemical Storage Liquid Pump & Solar Power Consumable Chemical Injection

12 Surfactant/foamer Capillary string installation

13 Advantage of capillary string

14 Vortex tool The path of least resistance for liquid and gas is determined to be of a helical trajectory (G.R Mingaleeva) Eliminate slip between liquid droplets and gas. Lower pressure drop due to friction. Lower critical velocity required to lift liquid.

15 Vortex surface tool

16 Vortex surface tool

17 Vortex downhole tool

18 Advantage of vortex tool Surfactant and Vortex tools

19 Advantage of vortex tool

20 Conclusion Installation of Vortex tool in bottom most landing nipple is an excellent combination. Using the two together (i.e., surfactant and vortex tools), we have seen reduction in surfactant use by 50%. The Vortex tool continually unloads the well as opposed to large slugs. It is therefore recommended to install vortex tool along with surfactant to optimize cost as well as production. Continuous injection should be the preferred solution for wells, where there is already chemical injection setup available. Vortex tool is recommended to be installed in the bottom most landing nipple. Application of Eductor on surface appears most economical and simple means to lower wellhead or line pressure.

21 Liquid unloading: Field glimpses

22 Thank You